Prior art hair cutting devices which incorporate a vacuum to remove cut hair include scissors or electric shears incorporated in a housing. The scissors and/or electric shears cut hair as it is being drawn into the housing by a vacuum. Examples of such devices are illustrated in U.S. Pat. Nos. 3,900,949; 4,473,945 and 4,679,322. An alternative arrangement is illustrated in U.S. Pat. No. 4,000,562 wherein a vacuum source is applied to an individual""s scalp and slots are incorporated in the vacuum source for scissors to cut the hair. Although these prior arrangements dispose of the cut hair, they have many disadvantages. A major disadvantage is that two hands are required to position the cutting apparatus on an individual""s scalp and to cut the hair. The use of two hands makes the cutting operation more difficult and does not give the operator a free hand to steady a cuttee""s head, or to comb or otherwise prepare a section of the hair while simultaneously cutting another section. Many of the prior art devices also do not incorporate an adequate vacuum sealing arrangement to insure that a proper vacuum is applied to the hair and to further prevent the hair from straying from the cutting zone. Prior art devices also suffer from back pressure flow problems during operation due to the hair inlet being blocked at times, the improper cutting or uneven cutting of the hair during operation and/or inadvertent tangling or pulling of the hair from the scalp of the individual during cutting. Such operations are unsatisfactory and painful to the individual. Electric cutters similar to ones illustrated in U.S. Pat. No. 4,679,322 are also heavy and very bulky due to the need for an electric motor and room for the complicated blade movement arrangement.
In view of the numerous disadvantages associated with prior art vacuum-assisted cutting devices, there has developed a need for a light-weight vacuum-assisted cutting device which can easily and effectively cut hair, can be positioned on an individual""s scalp and actuated by a single hand of an operator, and has a simple yet effective cutting mechanism. This invention satisfies the need.
Other advantages and attributes will be readily discernible upon a reading of the text hereinafter.
An object of the present invention is to provide a device for cutting hair which can be easily operated with a single hand, can easily and effectively cut an individual""s hair and can conveniently remove the cut hair from the cutting chamber.
Another object of the present invention is to provide a device for cutting hair which includes a vacuum source for drawing the hair from the cutting chamber.
Yet another object of the present invention is to provide a device for cutting hair which insures that the cutting blades are properly positioned when cutting an individual""s hair.
Still yet another object of the present invention is to provide a cutting mechanism which includes blades which lie in a cutting plane that is substantially perpendicular to the plane in which the hair is drawn into a cutting chamber.
Another object of the present invention is to provide a cutting mechanism wherein the blade edges of the blades are designed to cut hair in a guillotine fashion.
Still yet another object of the present invention is to provide a cutting mechanism which applies pressure to the blades which is preferably perpendicular, but can be at some other angle, to the cutting plane of the blades to insure that the blade edges are closely adjacent during the cutting of the hair.
Another object of the present invention is to provide a cutting mechanism wherein at least one blade has a bowed cutting edge angled with respect to the other blade which results in the cutting edges of each blade making shearing contact at a point which travels along the edges.
An additional object of the present invention is to provide a cutting mechanism wherein the airflow through the device aids in maintaining a positive shearing contact between the blades during the cutting action.
An additional object of the present invention is to provide a cutting mechanism wherein the airflow through the device is maintained regardless of the position of the blades during the cutting action.
Yet another object of the present invention is to provide an opening in the device for cutting which controls the amount of hair drawn into the cutting chamber to facilitate in the proper operation of the cutting device.
Another object of the present invention is to provide a device for cutting which includes a spacing mechanism for adjusting the length of hair to be cut.
In accordance with yet another feature of the present invention, the cutting mechanism includes at least two cutting blades. At least one of which is slidably moveable between an open position and a shear position. Preferably, the two blades are disposed within the cutting chamber in a plane which is substantially perpendicular to the plane in which the hair is being vacuum drawn into the chamber. This provides for an easier and more complete shearing of the hair. In the open position, the hair is drawn into the cutting chamber and between the cutting edges of the two blades. As the blades are moved toward the shear position, the hair disposed between the two blades is cut by the blades. The cut hair is then drawn through the hollow outlet body and into a disposal chamber of the vacuum source. Preferably, one of the blades is substantially affixed in a single position in the cutting chamber and the second blade is slidably moveable between the open position and the shear position. In the open position, the cutting edge of one blade is preferably spaced from the cutting edge of the second blade. When the hair is to be cut, at least one blade is drawn and/or pushed toward the second blade. This type of cutting arrangement greatly simplifies the design of the cutting arrangement and reduces the jamming or freezing of the blades during cutting since the blade edges completely separate after cutting as opposed to a constant blade overlapping design which is susceptible to jamming. The blade movement mechanism preferably directly applies the blade movement force. Indirect blade movement force arrangements such as those that incorporate a cam to move one or more blades significantly complicate the cutting arrangement, applying large indirect forces which are typically perpendicular to the plane of the movement of the blade thus making the blades more susceptible to damage and more susceptible to jamming. By directly drawing one blade toward another blade, only the needed force to cut the hair is applied to the blade. Such an arrangement greatly simplifies the design, operation and effectiveness of the cutting mechanism. Preferably, the two blades are biased in the open position and require the operator to manually activate the cutting mechanism to move the blades into the shear position. The blades can be biased in the open position by a spring or other resilient mechanism. The edges of the two blades may be designed so that they are not parallel, i.e. an edge is angled with respect to the other edge, so as to resemble a guillotine cutting arrangement. Such a blade edge design facilitates in the ease and efficiency of the cutting of the hair when the blades are moved into the shear position.
In accordance with yet another aspect of the present invention, the cutting chamber includes a pressure arrangement for applying pressure to at least one of the cutting blades. Preferably, the pressure applied is substantially perpendicular to the plane of movement of the blades between the open and shear positions. The applied pressure prevents the blades from separating as they move from the open position to the shear position. Unintended separation of the blades during cutting can result in uncut or miscut hair. The pressure arrangement may also be designed to allow the blades to slightly separate when cutting a large volume of hair and/or relatively thick hair to increase the ease and effectiveness of cutting large volumes of hair and/or very thick hair. The pressure arrangement preferably includes one or more springs and a pressure frame. The springs are preferably positioned to cause the pressure frame to be biased against one or more of the cutting blades. This spring arrangement both directs pressure to the blades and further allows the blades to slightly separate as described above. In a first embodiment, several springs are used in the pressure arrangement so that the pressure applied to the blades by the pressure frame is substantially uniform during the operation of the cutting mechanism. An alternate pressure arrangement uses resilient pads instead of springs to apply pressure to the pressure frame.
In accordance with still yet another aspect of the present invention, a blade guide is incorporated in the cutting mechanism to insure that the blades properly move between the open position and the shear position. The blade guide preferably limits the movement of the blades in a slot when the blades slide between the open position and the shear position. Preferably, the blade guide substantially affixes one of the cutting blades into a single position and provides a slot arrangement for the second blade to slide between the open and shear position. The slot arrangement also preferably allows the cutting edges of the two blades to slightly separate as they close together so that large volumes of hair and/or thick hair can be easily and effectively cut.
In accordance with another aspect of the present invention, at least one of the cutting blades includes a blade extension which extends between the two blades in both the open and shear position. The blade extension insures that when the blades move together, the cutting edges of the two blades do not abut against one another thus interfering with the cutting of the hair between the blades. As can be appreciated, other arrangements can be used to insure the proper position of the blades during the movement between the open position and the shear position.
In still yet another aspect of the present invention, at least one blade is bowed along the length of its edge. The bowed blade design ensures that the cutting edges of the blades meet at a shearing point which moves progressively along the edges as the blades close together.
In accordance with another aspect of the present invention, a slotted opening which includes at least one rake is connected to the opening of the inlet section. Preferably, two or more rakes are connected to the slotted opening. The rakes are preferably attached to and/or positioned adjacent to the slotted opening. The rakes and the slotted opening receive a defined volume of hair and direct such hair through the inlet section opening and into the cutting chamber. The slotted opening is preferably disposed to draw hair into the cutting chamber substantially perpendicular to the cutting plane of the blades. This alignment of the slot opening improves the ease and effectiveness of cutting hair, but it can be appreciated that the slotted opening can be positioned to direct hair into the cutting chamber angled to the cutting plane. The rakes are designed to comb the hair as the cutting device is moved on an individual""s head. The combing of the hair helps separate tangled hair so that the hair will be properly drawn into the cutting chamber. The rakes are preferably positioned substantially parallel to one another. The rakes extend from the slotted opening a distance which is sufficient to position the device on an individual""s head to provide sufficient spacing for air flow into the slotted opening. By providing sufficient air flow into the slotted opening while the cutting device is positioned on an individual""s head, the problems associated with static airflow in the cutting chamber and increased load on the vacuum source due to airflow blockage are essentially eliminated. It can be appreciated that additional air passageways can be incorporated into the cutting device to further prevent airflow blockage. It can be further appreciated that the rake surfaces can be curved to facilitate the movement of the rakes through an individual""s hair and to further ensure that air properly flows into the slotted opening.
In accordance with still yet another aspect of the present invention, a spacing device is connected between the slotted opening and the inlet opening. The spacing device allows the operator to cut the hair of an individual at a desired length. A longer spacer results in an individual having longer hair after the haircut whereas a shorter spacer results in shorter hair. The spacing device preferably has a cross-sectional shape which is substantially similar to the cross-sectional shape of the slotted opening and the inlet opening; however, it can be appreciated that the spacing device can have other cross-sectional shapes. The spacing device preferably is a substantially straight tubular device which does not alter the course of the hair entering into the slotted opening and extending into the cutting chamber; however, the spacing device may be angularly shaped.
The spacing device may include corrugated ribs to allow the spacing device to be easily adjustable between an angular and straight position to facilitate in the positioning of the cutting device during the cutting of an individual""s hair.
In accordance with yet another aspect of the present invention, the manual mechanism for operating the cutting mechanism includes a squeeze lever to the outlet body. The squeeze lever is preferably biased in the open position so that when the operator is not grasping the squeeze lever, the blades of the cutting mechanism are in the open position. When the squeeze lever is pivotally drawn toward the outlet section, it causes the blades of the cutting mechanism to move together to cut hair. As can be appreciated, the squeeze lever may be alternatively attached to a switch which activates and/or de-activates an electrical motor or the like that moves the blades.
These and other objects and advantages, expressed or implied, hereinafter are accomplished by a device for cutting hair which includes a cutting chamber is connected between an inlet section and an outlet section. The outlet section is connected to a vacuum source which creates a vacuum at the outlet section and causes air to be drawn into an opening in the inlet section. The air drawn into the inlet opening causes hair on an individual""s scalp to be drawn into the cutting chamber when the device is placed upon the head of an individual. Disposed in the cutting chamber is a cutting mechanism which cuts the hair being vacuum drawn into the cutting chamber. The cutting mechanism is preferably manually operated; however, it can be appreciated that the cutting mechanism may be operated by an electric motor or the like. The outlet section preferably includes an elongated hollow body which an operator can easily grasp to position the device at a desired area on an individual""s head. The cutting mechanism is manually activated by a switch or lever which is preferably located adjacent the grasping portion of the outlet body so that the operator can simultaneously position the cutting device and activate the cutting mechanism with a single hand.